79 research outputs found

    Habitat Condition and Associated Macrofauna Reflect Differences Between Protected and Exposed Seagrass Landscapes

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    Seagrass landscape configurations associated with different physical settings can affect habitat-structure and plant-animal relationships. We compared shoal grass (Halodule wrightii) habitat and macrofaunal variables between two fragmented seagrass landscapes at barrier-island locations subject to different disturbance regimes. Five seagrass habitat variables including above ground biomass (AGB), shoot number, per shoot biomass, epiphyte biomass and below ground biomass (BGB), differed significantly between the island landscapes. Per shoot biomass and epiphyte biomass also varied significantly over the seagrass growing season; and epiphyte biomass showed a strong landscape-time interaction. Abundances of microgastropods normalized to AGB differed significantly between landscapes. An inverse relationship between the abundance of microgastropods and epiphyte loading suggests a possible functional link. However, additional temporal mismatch between epiphyte loading and microgastropod abundance indicates that controls on epiphyte loading were complex. Seagrass habitat was more fragmented within the Cat Island (CI) landscape. Wind direction and strength imply that the CI landscape experienced more physical disturbance than the Horn Island (HI) landscape. This study highlights some potential links involving landscape configuration, habitat structure, and macrofaunal associations which can be further addressed using hypothesis-driven research

    Two-microphone spatial filtering provides speech reception benefits for cochlear implant users in difficult acoustic environments

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    This article introduces and provides an assessment of a spatial-filtering algorithm based on two closely-spaced (∌1 cm) microphones in a behind-the-ear shell. The evaluated spatial-filtering algorithm used fast (∌10 ms) temporal-spectral analysis to determine the location of incoming sounds and to enhance sounds arriving from straight ahead of the listener. Speech reception thresholds (SRTs) were measured for eight cochlear implant (CI) users using consonant and vowel materials under three processing conditions: An omni-directional response, a dipole-directional response, and the spatial-filtering algorithm. The background noise condition used three simultaneous time-reversed speech signals as interferers located at 90°, 180°, and 270°. Results indicated that the spatial-filtering algorithm can provide speech reception benefits of 5.8 to 10.7 dB SRT compared to an omni-directional response in a reverberant room with multiple noise sources. Given the observed SRT benefits, coupled with an efficient design, the proposed algorithm is promising as a CI noise-reduction solution.National Institutes of Health (U.S.) (Grant R01 DC 000117)National Institutes of Health (U.S.) (Grant R01 DC DC7152)National Institutes of Health (U.S.) (Grant 2R44DC010524-02

    Spleen Vagal Denervation Inhibits the Production of Antibodies to Circulating Antigens

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    BACKGROUND: Recently the vagal output of the central nervous system has been shown to suppress the innate immune defense to pathogens. Here we investigated by anatomical and physiological techniques the communication of the brain with the spleen and provided evidence that the brain has the capacity to stimulate the production of antigen specific antibodies by its parasympathetic autonomic output. METHODOLOGY/PRINCIPAL FINDINGS: This conclusion was reached by successively demonstrating that: 1. The spleen receives not only sympathetic input but also parasympathetic input. 2. Intravenous trinitrophenyl-ovalbumin (TNP-OVA) does not activate the brain and does not induce an immune response. 3. Intravenous TNP-OVA with an inducer of inflammation; lipopolysaccharide (LPS), activates the brain and induces TNP-specific IgM. 4. LPS activated neurons are in the same areas of the brain as those that provide parasympathetic autonomic information to the spleen, suggesting a feed back circuit between brain and immune system. Consequently we investigated the interaction of the brain with the spleen and observed that specific parasympathetic denervation but not sympathetic denervation of the spleen eliminates the LPS-induced antibody response to TNP-OVA. CONCLUSIONS/SIGNIFICANCE: These findings not only show that the brain can stimulate antibody production by its autonomic output, it also suggests that the power of LPS as adjuvant to stimulate antibody production may also depend on its capacity to activate the brain. The role of the autonomic nervous system in the stimulation of the adaptive immune response may explain why mood and sleep have an influence on antibody production

    Thienoisoindigo-Based Semiconductor Nanowires Assembled with 2-Bromobenzaldehyde via Both Halogen and Chalcogen Bonding

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    We fabricated nanowires of a conjugated oligomer and applied them to organic field-effect transistors (OFETs). The supramolecular assemblies of a thienoisoindigo-based small molecular organic semiconductor (TIIG-Bz) were prepared by co-precipitation with 2-bromobenzaldehyde (2-BBA) via a combination of halogen bonding (XB) between the bromide in 2-BBA and electron-donor groups in TIIG-Bz, and chalcogen bonding (CB) between the aldehyde in 2-BBA and sulfur in TIIG-Bz. It was found that 2-BBA could be incorporated into the conjugated planes of TIIG-Bz via XB and CB pairs, thereby increasing the pi - pi stacking area between the conjugated planes. As a result, the driving force for one-dimensional growth of the supramolecular assemblies via pi - pi stacking was significantly enhanced. TIIG-Bz/2-BBA nanowires were used to fabricate OFETs, showing significantly enhanced charge transfer mobility compared to OFETs based on pure TIIG-Bz thin films and nanowires, which demonstrates the benefit of nanowire fabrication using 2-BB

    Sex-Specific Growth and Reproductive Dynamics of Red Drum in the Northern Gulf of Mexico

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    The Red Drum Sciaenops ocellatus stock is heavily targeted in the Gulf of Mexico (GOM) by recreational fishers and supports a small commercial fishery in Mississippi. Despite their popularity, little recent work has been done to describe their life history. In this work, we describe sex‐specific growth and reproductive dynamics of Red Drum collected from the northern GOM from September 2016 through October 2017. We evaluated seven candidate growth models and found that the three‐parameter von Bertalanffy growth function (VBGF) was the best candidate length‐at‐age model. No significant difference in growth between sexes was observed with the three‐parameter VBGF, despite the female‐specific curve having a larger mean asymptotic length than the male‐specific curve. All seven candidate growth models predicted similar mean length‐at‐age estimates, and four of them exhibited significant differences in sex‐specific mean length at age, with females reaching a larger length at age than males after age 5. There was no significant difference between the sex‐specific weight‐at‐length relationships. Red Drum are batch spawners that spawn in northern GOM coastal waters during August and September. We estimated 3.7 d between spawns and 10.5 spawning events per female in 2017. Nearly 20% of fish collected during the spawning season were sexually mature but reproductively inactive, indicating the possibility of skipped spawning. The age at 50% maturity was around 3 years (length at 50% maturity = 670 mm TL) in both sexes, but fish were not spawning capable until age 4.5 (703 mm TL) in males and age 5.8 (840 mm TL) in females. Furthermore, elevated gonadosomatic indices were not observed until around age 5–6. The updated life history information presented in this work helps to address current data limitations and provides critical information for future assessments of Red Drum stocks in the northern GOM

    Nutrition policy in Burkina Faso

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    This brief summarizes nutrition-relevant policies in Burkina Faso. We examine i) nutrition context, policy objectives, indicators, budget, and activities, ii) key beneficiaries, actors and coordination, iii) monitoring, evaluation, and accountability, and iv) whether current policies are aligned with the World Health Assembly (WHA) global targets.Non-PRIFPRI1; CRP4; 2 Promoting Healthy Diets and Nutrition for all; Transform Nutrition West AfricaPHND; A4NHCGIAR Research Program on Agriculture for Nutrition and Health (A4NH

    Polyvinylpyrrolidone Molecular Weight Controls Silica Shell Thickness on Au Nanoparticles with Diglycerylsilane as Precursor

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    Several strategies have been described for the preparation of silica-encapsulated gold nanoparticles (SiO<sub>2</sub>–AuNP), which typically suffer from an initial interface between gold and silica that is difficult to control, and layer thicknesses that are very sensitive to minor changes in silane concentration and incubation time. The silica shell thicknesses are normally equal to or larger than the gold particles themselves, which is disadvantageous when the particles are to be used for biodiagnostic applications. We present a facile and reproducible method to produce very thin silica shells (3–5 nm) on gold nanoparticles: the process is highly tolerant to changes in reaction conditions. The method utilized polyvinylpyrrolidone (PVP) of specific molecular weights to form the interface between gold and silica. The method further requires a nontraditional silica precursor, diglycerylsilane, which efficiently undergoes sol–gel processing at neutrality. Under these conditions, higher molecular weight PVP leads to thicker silica shells: PVP acts as the locus for silica growth into an interpenetrating organic–inorganic hybrid structure
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